The bacterial zoo inside your gut could look very different if you're a vegetarian or an Atkins dieter, a couch potato or an athlete, fat or thin.

Now for a fee – $69 and up – and a stool sample, the curious can find out just what's living in their intestines and take part in one of the hottest new fields in science.

Wait a minute: How many average Joes really want to pay for the privilege of mailing such, er, intimate samples to scientists?

A lot, hope the researchers running two novel citizen-science projects.

One, the American Gut Project, aims to enroll 10,000 people – and a bunch of their dogs and cats too – from around the country. The other, uBiome, separately aims to enroll nearly 2,000 people from anywhere in the world.